Rebar tie wire reels for reinforcing bar binding machinery

ABSTRACT

A rebar tie wire reel (110) for a reinforcing bar binding machine has a first flange (118), a second flange (120) spaced from the first flange, a hub connecting the first and second flanges and a wire (124) wound around the hub. The first flange (118) has an outwardly facing major face (134) and an outer periphery. The outer periphery is defined by a plurality of edges (170, 172, 174, 176). The plurality edges include a first edge (170) and a second edge (172) that are configured such that, in use, an amount of rotation of the rebar tie wire reel can be determined using signals provided by a movable element of a contact sensor when during rotation of the wire reel, the first edge, major face and the second edge successively travel past the movable element.

FIELD OF THE INVENTION

The invention relates to rebar tie wire reels for reinforcing bar binding machinery.

BACKGROUND TO THE INVENTION

Known reinforcing bar binding machines may comprise a chamber in which a rebar tie wire reel is mounted. Such binding machines may comprise a wire feed mechanism configured to draw wire from the rebar tie wire reel and feed it through a guide device that is configured to cause the wire to loop around a pair of reinforcing bars that are to be bound and a twisting device that can engage the looped wire and apply a twisting force by which the loops are tightened around the reinforcing bars. The rebar tie wire reel may comprise a hub with respective flanges at the ends of the hub and a wire wound onto the hub between the flanges. The rebar tie wire reel may be provided with markings that can be detected by sensors provided in the binding machine to enable the wire type and amount of rotation of the rebar tie wire reel to be determined.

SUMMARY OF THE INVENTION

The invention provides a rebar tie wire reel as specified in claim 1.

The invention also includes a method of sensing rotation of a rebar tie wire reel as specified in claim 13.

The invention also includes a rebar tie wire reel as specified in claim 18.

The invention also includes a method of manufacturing a rebar tie wire reel as specified in claim 19.

The invention also includes a rebar tie wire reel as specified in claim 20.

The invention also includes a rebar tie wire reel as specified in claim 21.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following disclosure, reference will be made to the drawings, in which:

FIG. 1 is a schematic representation of a reinforcing bar binding machine;

FIG. 2 is a schematic rear end view of the reinforcing bar binding machine with a rear end wall omitted to show a chamber that in use houses a rebar tie wire reel;

FIG. 3 is a schematic side view of a rebar tie wire reel for the reinforcing bar binding machine of FIGS. 1 and 2;

FIG. 4 is a schematic side view of the rebar tie wire reel of FIG. 4;

FIG. 5 is a schematic side view illustrating a modification to the rebar tie wire reel of FIGS. 3 and 4; and

FIG. 6 is a schematic plan view of the modified rebar tie wire reel of FIG. 5.

DETAILED DESCRIPTION

Referring to FIG. 1, a reinforcing bar binding machine 10 comprises a casing 12 and a handle 14 that may be an integral part of the casing. The casing 12 may define a sidewall 16, an inner end wall 18, an outer end wall 20 and a bottom wall 22 that define a chamber 24 in which a rebar tie wire reel (not shown) can be mounted. The casing 12 may additionally define an opening disposed generally opposite the sidewall 18 that may be closed by a cover member 26. The cover member 26 may carry a reel mounting shaft 28 on which a rebar tie wire reel may be mounted and the sidewall 16 may be provided with a boss 30 that is axially aligned with the shaft 28. The cover member 26 may be hinge connected to the casing 12 and may be provided with a locking device engageable with a cooperating device provided on the casing 12 to lock the cover member in a chamber closing position. The boss 30 may be configured to locate in a recess provided in a rebar tie wire reel to assist in correctly and stably locating the rebar tie wire reel in the chamber 24.

The reinforcing bar binding machine 10 may be provided with a wire feed mechanism 32 that is driven by an electric motor 34. The wire feed mechanism 32 may comprise a pair of meshing gears provided with integral feed rollers. A tie wire from a rebar tie wire reel mounted in the chamber 24 may be fed through an opening 36 in the inner end wall 18 between the feed rollers so that it is drawn from the rebar tie wire reel when the gears are driven by the electric motor 34.

The reinforcing bar binding machine 10 may be provided with a guide system 38 through which the tie wire drawn from the rebar tie wire reel by the feed mechanism 32 is fed towards the leading end 40 of the machine. The guide system 38 includes a curved portion 42 disposed at the leading end 40. The curved portion 42 of the guide system 38 is configured to cause the wire to curl to form a loop. A wire cutter 44 is provided at the leading end 40.

The reinforcing bar binding machine 10 may be provided with a wire twisting device 50 that is actuated by an electric motor 52. The wire twisting device 50 may comprise a fork or hook 54 that can be driven back and forth to engage a tie wire looped around reinforcing bars and rotated to twist the tie wire and thereby bind the reinforcing bars.

The reinforcing bar binding machine 10 may be provided with a wire reel detection system that comprises a contact sensor 60 and a non-contact sensor 62. The contact sensor 60 may comprise an electric switch that has a movable element 64 disposed in the chamber 24. The movable element 54 may protrude from an opening in the sidewall 16 to an engagement position at which it can be engaged by a flange of a rebar tie wire reel mounted on the shaft 28. The movable element 64 may be maintained in the engagement position by one or more resilient biasing elements, which may include a compression spring. The non-contact sensor 62 may comprise an optical sensor comprising a light-emitting device 66 and a light receiving device 68 disposed generally opposite the light-emitting device. The light-emitting device 66 may be mounted in the boss 30 and the light receiving device 68 may be carried by the cover member 26.

The contact sensor 60 and non-contact sensor 62 may be connected with a controller 74 that is configured to process signals from the sensors 60, 62 to determine at least one of wire type and an amount of rotation of a rebar tie wire reel mounted on the shaft 28. The controller 74 may be a microprocessor-based controller that is additionally configured to control operation of the feed mechanism 32 and twisting device 50. The controller 74 may be configured to control the amount of tie wire fed by the feed mechanism 32 and the twisting torque applied to the tie wire by the wire twisting device 50 based on determinations made using signals received from the sensors 60, 62

Referring to FIGS. 3 and 4, a rebar tie wire reel 110 that may be used with a reinforcing bar binding machine such as the reinforcing bar binding machine 10 shown in FIGS. 1 and 2 comprises a hub 112 having a first end 114 and a second end 116 opposite the first end, a first flange 118 disposed at the first end 114, a second flange 120 disposed at the second end 116 and a rebar tie wire 124 wound around the hub 112. The hub 112 and first and second flanges 118, 120 may be a plastics moulding. A plastics moulding may be made of ABS resin, polyethylene or polypropylene or any other suitable plastics material that may have good resistance to bending and wear. The plastics moulding is preferably made of a black plastics material. Thus, the hub 112, first flange 114 and second flange 120 may be produced as one piece.

The hub 112 may be provided with an axially extending through-hole 130 defined by an inwardly facing wall 132 of the hub 112. The through-hole 130 may extend from an outwardly facing major face 134 of the first flange 118 to an outwardly facing major face 136 of the second flange 120. A tubular reel mounting member 138 may be provided in the through-hole 130. The reel mounting member 138 may be attached the inwardly facing wall 132 of the hub 112 by a wall 140 that extends from the inwardly facing wall to an outwardly facing wall 142 of the reel mounting member 138. The wall 140 may be disposed at least substantially perpendicular to the axis of rotation 144 of the rebar tie wire reel 110. The axis of rotation 144 is defined by the reel mounting member 138 and may be coincident with the longitudinal axis of the through-hole 130, or the hub 112. Radial support struts (not shown) may be provided between the hub 122 and reel mounting member 138 to support the reel mounting member. Such support struts may be provided above or below the wall 140 or both. The support struts may comprise generally planar bodies extending radially with respect to the axis of rotation 144. The reel mounting member 138 may comprise a lengthways extending aperture configured to be a sliding fit on the shaft 28 so that the rebar tie wire reel 110 can be mounted on and rotate relative to the shaft to allow tie wire 124 to be drawn from the rebar tie wire reel by the wire feed mechanism 32. The first flange 118 may be provided with a recess 152 surrounding the through-hole 130. The recess 152 may be configured to receive the boss 30 so that the boss can provide support for the rebar tie wire reel 110 when mounted on the shaft 28.

As shown in FIG. 4, at least one through-hole 158 may be provided in the wall 140. The or each through-hole 158 is configured such that light emitted by the light emitting device 66 can pass through the rebar tie wire reel via the through-hole 130 to be received by the light receiving device 68. The or each through-hole 158 may comprise a radially extending slit, which may have a length greater than its width.

The second flange 120 may have a generally circular outer periphery 162. In some examples, the outer periphery 162 may configured to define a series of equi-spaced teeth 164 (only two of which are shown in FIG. 4 for ease of representation). The teeth 164 may be configured to be engageable with a braking mechanism 166 (FIG. 2) of the reinforcing bar binding machine 10.

As best seen in FIG. 4, the first flange 118 has an outer periphery comprising a plurality of edges 170, 172, 174, 176. As described in more detail below, a first edge 170 and a second edge 172 are configured such that, in use, an amount of rotation of the rebar tie wire reel 110 can be determined using signals provided by the movable element 64 of the contact sensor 60 as, during rotation of the rebar tie wire reel, the first edge, major face 134 and the second edge successively travel past the movable element.

The major face 134 may comprise a planar surface. However, this is not essential an in some examples a non-planar major face 134 may be provided with a flat surface portion extending between the first and second edges 170, 172 that is configured such that, in use, it is engaged by the movable element 64 when first edge, the major face 134 and the second edge successively travel past the movable element. It may, for example be desirable, to provide cut-outs (not shown) in the major face 134 for weight reduction or material saving purposes or for ease of moulding, for example to reduce shrinkage problems that may arise when relatively thick sections cool after moulding.

Although not essential, in the illustrated example, the first and second edges 170, 172 are straight edges. The first and second edges 170, 172 may extend in parallel spaced apart relation as shown in FIG. 4. The first and second edges 170, 172 may be joined by a third edge 174 and fourth edge 176 that are each curved. Preferably the curved edges 174, 176 represent segments of a circle having a diameter corresponding to the diameter of the second flange 120.

In use, the rebar tie wire reel 110 may be loaded into the chamber 24 by opening the cover member 26 and inserting the shaft 28 into the reel mounting member 138. The cover member 26 may then be closed bringing the shaft 20 into alignment with the boss 30, which engages in the recess 152. The rebar tie wire reel 110 is thus stably mounted for rotation on the shaft 28. A free end (not show) of the tie wire 124 can then be threaded through the opening 36 in the inner end wall 18 to engage with the wire feed mechanism 32. The wire feed mechanism 32 can be actuated by the electric motor 34 in response to pressure applied by a user to a trigger 168. When the wire feed mechanism 32 is actuated, tie wire 124 is drawn from the rebar tie wire reel 110 and fed towards the leading end 40 of the reinforcing bar binding machine 10. As the tie wire 124 advances towards the leading end 40 it is guided by the guide system 38. As the wire passes through the curved portion 42 of the guide system 38, it may loop around reinforcing bars (not shown) disposed adjacent the leading end 40 in a way that will be known to those skilled in the art. Once sufficient tie wire 124 is looped around the reinforcing bars, the tie wire may be cut using the cutting device 44 and the loop twisted by the wire twisting mechanism 50 to tighten it around the reinforcing bars. The wire twisting mechanism 50 may be actuated by the electric motor 52 in response to a second operation of the trigger 168.

When the wire feed mechanism 32 is actuated to draw tie wire 124 from the rebar tie wire reel 110, the rebar tie wire reel rotates on the shaft 28. As the rebar tie wire reel 110 rotates (clockwise in the illustrated example), the first edge 170 of the first flange 118 is brought into engagement with an engagement edge 70 of the movable element 64 of the contact sensor 60, which is depressed, or pushed into the side wall 16. The movable element 64 may be inclined at the engagement edge 70 so that the first edge 170 is able to progressively engage the engagement edge and depress the moveable element. As the major face 134 of the first flange 118 moves past the movable element 64 it engages the movable element and maintains it in its depressed condition. When the second edge 172 moves past the edge 72 of the movable element 64 disposed opposite the engagement edge 70, the movable element is disengaged from the major face 134 and is able to resume it non-depressed (or extended) condition. Thus, as the first then second edges 170, 172 the contact sensor 60 operates as a switch providing an electric signal to the controller 74. Continued rotation of the rebar tie wire reel 110 brings the second edge 172 into engagement with the movable element 64 causing it to depress again and again, the movable element is held in a depressed condition by engagement with the major face 134 until the first edge 170 again moves past the movable element allowing it to a resume its non-depressed (or extended) condition. Again, the depression and then release of the movable element 64 causes the contact sensor 60 to act as a switch providing an electric signal. Thus, for a full 360° rotation of the rebar tie wire reel 110, the contact sensor 60 will switch twice causing two signals to be sent to the controller 74.

As the rebar tie wire reel 110 rotates, the through-holes 158 are periodically brought into alignment with the light transmitting device 64 and light receiving device 66 of the non-contact sensor 62 so that pulses of light from the light transmitting device are received at the light receiving device. This causes pulse signals to be output to the controller 74.

The controller 74 may process the signals provided by actuation of the contact sensor 60 to determine the amount of rotation of the rebar tie wire reel. Alternatively, or additionally, the processor 74 may process the signals to determine count periods during which pulse signals from the non-contact sensor are counted. The counting of the pulsed signals may be used to determine the wire size or type so that the controller can determine the torque to be applied by the wire twisting mechanism or the amount of rotation of the rebar tie wire reel 110. Thus, for example, the through-holes 158 may be distributed about the reel mounting member 138 such that during a first count period the number of pulses is processed to determine the wire type and the combined pulse count for two count periods is processed to determine an amount of rotation.

The use of flange edges 170, 172 to determine a switching period of the contact sensor 60 allows the provision of a simple flange structure that may comprise a planar major face 134, or at least flat surface portions between the edges 170, 172 where the major face 134 is engaged by the movable element 64 of the contact sensor. It is not necessary to provide complicated topographies with projections or depressions to actuate the contact sensor. Furthermore, the edges 170, 172 may be provided by simply omitting opposed segments of a nominally circular flange, thereby making the rebar tie wire reel lighter and saving on material.

As indicated by the dashed line 180 in FIG. 3 when the rebar tie wire reel 110 is fully loaded with wire 124, the wire pack is not fully contained in the space defined between opposing inner faces 182, 184 of the first and second flanges 118 120. For the purposes of winding the wire 124 onto the hub 112 during manufacture, it may be desirable for the surface areas of the opposed inner faces 182, 184 to be at least substantially the same so that, as indicated by the dashed lines 182 in FIG. 5, the wire pack may be at least substantially fully contained between the first and second flanges 118, 120 during the winding on process. Once the wire winding process is completed, the first and second edges 170, 172 can then be provided by removing segments 112S of the first flange 118. This may be achieved by cutting the segments away. In some examples, as illustrated by FIG. 6, the first flange 118 may be provided with lines of weakness 186 that allow segments 112S to be snapped, or broken away from the main portion of the first flange to define the first and second edges. In cases in which the material from which the hub and flanges is made of is recyclable, the removed segments 112S may be reused allowing material and weight savings to be achieved.

In the illustrated examples, it can be seen that the opposing inner faces of the first and second flanges are disposed at least substantially parallel to one another and perpendicular to the axis of rotation of the rebar tie wire reel.

In the illustrated example, the first and second edges of the flange that engages the contact sensor are disposed in parallel spaced apart relation. This is not essential. In other examples, the first and second edges may be mutually inclined so that as the rebar tie wire reel rotates through 360 degrees the contact sensor provides two signals of differing duration. 

1. A rebar tie wire reel for a reinforcing bar binding machine, said rebar tie wire reel comprising: a first flange; a second flange spaced from said first flange; a hub connecting said first and second flanges; and a rebar tie wire wound around said hub, wherein said first flange has an outwardly facing major face and an outer periphery, said outer periphery is defined by a plurality of edges comprising a first edge and a second edge that faces away from said first edge, and said first and second edges and said outwardly facing major surface are configured such that, in use, an amount of rotation of the tie wire reel can be determined using signals trigged by a movable element of a contact sensor when during rotation of said rebar tie wire reel, said first edge, said major face and said second edge successively travel past said movable element to cause a said signal to be provided.
 2. A rebar tie wire reel as claimed in claim 1, wherein said major surface is provided with a flat surface portion extending between said first and second edges which, in use, is engaged by said movable element when said first edge, said major face and said second edge successively travel past said movable element.
 3. A rebar tie wire reel as claimed in claim 1, wherein said major face comprises a planar surface.
 4. A rebar tie wire reel as claimed in claim 1, wherein said first and second edges are straight edges.
 5. A rebar tie wire reel as claimed in claim 1, wherein, said first and second edges are disposed in parallel spaced apart relation.
 6. A rebar tie wire reel as claimed in claim 1, wherein said first and second edges are joined by a third edge and a fourth edge that is disposed opposite and spaced from said third edge.
 7. A rebar tie wire reel as claimed in claim 6, where said third and fourth edges are oppositely curved edges.
 8. A rebar tie wire reel as claimed in claim 7, wherein said first and second edges define chords of an imaginary circle having a diameter defined by said third and fourth edges.
 9. A rebar tie wire reel as claimed in claim 1, wherein said first flange, second flange and hub are a plastics moulding.
 10. A rebar tie wire reel as claimed in claim 1, wherein said hub has a longitudinal axis, first flange has an inner face, said second flange has an inner face and said inner faces are disposed at least substantially perpendicular to said longitudinal axis.
 11. A rebar tie wire reel as claimed in claim 1, wherein said hub comprises an internally disposed transverse wall and at least one through-hole is provided in said transverse wall for the passage of light emitted, in use, by a non-contact sensor of said reinforcing bar binding machine.
 12. A reinforcing bar binding machine comprising a chamber, a reel mounting disposed in said chamber, a contact sensor having a movable element and a rebar tie wire reel mounted on said reel mounting in said chamber, wherein: said rebar tie wire reel comprises: a first flange having an outwardly facing major face and an outer periphery defined by a plurality of edges comprising a first edge and a second edge; a second flange spaced from said first flange; a hub connecting said first and second flanges; and a rebar tie wire wound around said hub, and wherein, in use, an amount of rotation of the tie wire reel about said reel mounting is determined using signals triggered by said movable element when during rotation of said rebar tie wire reel, said first edge, said major face and said second edge successively travel past said movable element to cause a said signal to be provided.
 13. A method of sensing rotation of a rebar tie wire reel in a reinforcing bar binding machine comprising a contact sensor that has a movable element, said method comprising: causing said rebar tie wire reel to rotate so that a surface portion of an outwardly facing major face of a first flange of said rebar tie wire reel engages said movable element between a first edge of an outer periphery of said flange and a second edge of said outer periphery that is spaced apart from said first edge whereby said contact sensor is caused to provide a signal to a processor.
 14. A method as claimed in claim 13, wherein said first and second edges are configured to cause said contact sensor to provide two said signals for each 360 degrees of rotation of said rebar tie wire reel.
 15. A method as claimed in claim 13, further comprising processing signals provided by said contact sensor to determine an amount of rotation of said rebar tie wire reel.
 16. A method as claimed in claim 13, wherein said surface portion is planar.
 17. A method as claimed claim 13, further comprising detecting at least one through-hole provided in an internally disposed transverse wall of a hub of said rebar tie wire reel with a non-contact sensor and processing signals provided by said non-contact sensor and said contact sensor with said processor to determine at least one of type and size of a tie wire.
 18. A rebar tie wire reel for a reinforcing bar binding machine, said rebar tie wire reel comprising: a first flange; a second flange spaced from said first flange; a hub connecting said first and second flanges; and a rebar tie wire wound around said hub, wherein said first flange has an outwardly facing major face and an outer periphery, said first flange is provided with weakening portions whereby a plurality of segments of said first flange can be broken away so that said outer periphery is defined by a plurality of edges comprising a first edge and a second edge that faces away from said first edge, and said first and second edges and major face are configured such that, in use, an amount of rotation of the rebar tie wire reel can be determined using signals triggered by a movable element of a contact sensor when during rotation of said rebar tie wire reel, said first edge, said major face and said second edge successively travel past said movable element.
 19. A method of manufacturing a rebar tie wire reel for a reinforcing bar binding machine, said method comprising: winding a rebar tie wire onto a hub between a first flange and a second flange; and removing portions of said first flange so that said first flange comprises a plurality of edges including a first edge and a second edge that is spaced apart from said first edge and faces away from said first edge and an outwardly facing surface portion that defines a flat track that extends between said first and second edges, wherein said first and second edges and flat track are configured so that, in use in a reinforcing bar binding machines, as said rebar tie wire reel is rotated by the reinforcing bar binding machine so that said first edge, said flat track and said second edge successively move past a movable contact element of said reinforcing bar binding machine, said movable contact element is moved to cause triggering of a signal by which an amount of rotation of said rebar tie wire reel is determined.
 20. A rebar tie wire reel for a reinforcing bar binding machine, said rebar tie wire reel comprising: a first flange; a second flange spaced from said first flange; a hub connecting said first and second flanges; and a rebar tie wire wound around said hub, wherein said first flange has an outwardly facing major face and an outer periphery, and said outer periphery is defined by a plurality of edges comprising a first edge and a second edge that is spaced apart from said first edge such that, in use, as said rebar tie wire reel is rotated a surface portion of said major face extending between said first and second edges engages said movable element to cause said contact sensor to provide a signal to a processor as said first edge, surface portion and second edge successively move past said movable element.
 21. A rebar tie wire reel for a reinforcing bar binding machine, said rebar tie wire reel comprising: a first flange; a second flange spaced from said first flange; a hub connecting said first and second flanges and defining an axis of rotation of the rebar tie wire reel; and a rebar tie wire wound around said hub, wherein said first flange has an outwardly facing major face and an outer periphery, and said outer periphery is defined by a plurality of edges comprising a first straight edge, a second straight edge disposed opposite and spaced apart from and facing away from said first edge, a third edge extending between said first and second edge and a fourth edge extending between said first and second edges and disposed opposite and spaced apart from said third edge, said first straight edge and said second straight edge being arranged such that, in use, when mounted in a reinforcing bar binding machine having a contact sensor comprising a movable element, rotation of the rebar tie reel through 360 about said axis of rotation causes each of said first and second edges to pass under said movable element.
 22. A rebar tie wire reel as claimed in claim 21, wherein said first and second edges are parallel edges.
 23. A rebar tie wire reel as claimed in claim 21, wherein said third and fourth edges are oppositely curved surfaces.
 24. A rebar tie wire reel as claimed in claim 23, wherein said first and second edges define chords of an imaginary circle having a diameter defined by said third and fourth edges. 